The provision of thin metal films on polymeric material webs by vapour deposition, usually of aluminum, is well known. The polymeric film passes continuously through a vacuum chamber containing the metal vapor, which deposits on one surface of the film.
It has previously been described by Donald E. Beckett in U.S. Pat. Nos. 4,398,994, 4,556,614 and 4,610,755 to form decorative patterns on metallized polymeric films by selective demetallization of the aluminum using a suitable aqueous etchant. Details of the procedures used are set forth in the above-noted patents.
While the prior art selective demetallizing processes successfully produce patterned films for packaging and other purposes, it is necessary to remove metal previously applied to the substrate using chemical etchants, thereby incurring a considerable material cost.